Altered gene expression and PTSD symptom dimensions in World Trade Center responders

An Update on the Psychiatric Genomics of Posttraumatic Stress Disorder (PTSD)

Posttraumatic Stress Disorder (PTSD) is a prevalent psychiatric condition characterized by intrusive thoughts, hyperarousal, avoidance, and negative cognitive alterations following traumatic events. While a significant portion of individuals experience trauma, only 5% to 30% develop PTSD, with certain groups at higher risk. Research indicates that PTSD's pathophysiology involves altered fear processing, neuroendocrine dysfunction, and immune system changes. Genetic studies, particularly twin studies, suggest a heritability estimate of 30% to 40% for PTSD. Initially focused on gene-environment interactions, recent advancements in genome-wide association studies have identified significant genetic markers enhancing understanding of PTSD's genetic underpinnings.

Implications of gene × environment interactions in post-traumatic stress disorder risk and treatment

Exposure to traumatic stress is common in the general population. Variation in the brain's molecular encoding of stress potentially contributes to the heterogeneous clinical outcomes in response to traumatic experiences. For instance, only a minority of those exposed to trauma will develop post-traumatic stress disorder (PTSD). Risk for PTSD is at least partially heritable, with a growing number of genetic factors identified through GWAS. A major limitation of genetic studies is that they capture only the genetic component of risk, whereas PTSD by definition requires an environmental traumatic exposure. Furthermore, the extent, timing, and type of trauma affects susceptibility. Here, we discuss the molecular mechanisms of PTSD risk together with gene × environment interactions, with a focus on how either might inform genetic screening for individuals at high risk for disease, reveal biological mechanisms that might one day yield novel therapeutics, and impact best clinical practices even today. To close, we discuss the interaction of trauma with sex, gender, and race, with a focus on the implications for treatment. Altogether, we suggest that predicting, preventing, and treating PTSD will require integrating both genotypic and environmental information.

Gene expression and epigenetic changes in post-traumatic stress disorder, depression, and anxiety in first responders: A systematic review

OBJECTIVE

Police, firefighters, dispatchers, and emergency medical technicians-collectively known as first responders-are a unique population frequently exposed to chronic, traumatic incidents. This exposure results in a high prevalence of PTSD, depression, and anxiety, posing a substantial public health concern. Genetic predispositions and epigenetic modifications that regulate gene expression are significant contributors to trauma-related pathologies. This systematic review aims to summarize current data on epigenetic and gene expression changes in first responders related to three post-trauma pathologies: PTSD, depression, and anxiety. We also explore genetic pathways across these disorders to identify potential commonalities and therapeutic targets.

METHODS

Following PRISMA guidelines, databases were searched from July to October 2023, yielding 1103 studies, 12 of which met the inclusion criteria (total N = 6943).

RESULTS

Of the included studies, 11 examined PTSD, consistently implicating stress-response genes, such as those in the hypothalamic-pituitary-adrenal axis (e.g., FKBP5, NR3C1), and genes related to inflammation and immune responses. Three studies focused on depression-related genetic biomarkers but reported no significant genome-wide methylation differences between responders with current versus no major depressive disorder (MDD). No studies addressed epigenetic or gene expression changes linked to anxiety.

CONCLUSION

This review identified novel genes and pathways related to trauma as potential targets for future research and pharmacological therapy. It also highlights a significant gap in the literature, emphasizing the need for broader research to investigate the genetic underpinnings of trauma exposure in first responders, aiming to identify relevant pathways and therapeutic targets.

Transcriptomics and psychotherapy: An integrative review

Gold-standard psychotherapies like cognitive-behavioral therapy (CBT) show beneficial effects, but patient responses vary, indicating a need to predict and optimize treatment efficacy. Gene expression analysis may offer insights into the interplay between psychosocial processes and biological factors that impact psychopathology and therapeutic response. This integrative review examines 17 studies that assess gene expression in the context of psychotherapy, highlighting innovative frameworks for incorporating gene expression analysis in diagnosis, predicting treatment response, and monitoring treatment progress. Current evidence points to transcriptional control pathways downstream of the hypothalamic-pituitary-adrenal (HPA)-axis and sympathetic nervous system (SNS) signaling pathways, particularly their effects on immune cells (e.g., pro-inflammatory processes and wound healing), as key areas for future research. Higher-level pathway analyses, whether theory-based or empirically driven, appear to offer the most robust framework for future studies. This review also discusses significant limitations of current literature and proposes directions for future research.

Mapping the epigenomic landscape of post-traumatic stress disorder in human cortical neurons

The study conducted a comprehensive genome-wide analysis of differential 5mC and 5hmC modifications at both CpG and non-CpG sites in postmortem orbitofrontal neurons from 25 PTSD cases and 13 healthy controls. It was observed that PTSD patients exhibit a greater number of differential 5hmC sites compared to 5mC sites. Specifically, individuals with PTSD tend to show hyper-5mC/5hmC at CpG sites, particularly within CpG islands and promoter regions, and hypo-5mC/5hmC at non-CpG sites, especially within intragenic regions. Functional enrichment analysis indicated distinct yet interconnected roles for 5mC and 5hmC in PTSD. The 5mC marks primarily regulate cell-cell adhesion processes, whereas 5hmC marks are involved in embryonic morphogenesis and cell fate commitment. By integrating published PTSD findings from central and peripheral tissues through multi-omics approaches, several biological mechanisms were prioritized, including developmental processes, HPA axis regulation, and immune responses. Based on the consistent enrichment in developmental processes, we hypothesize that if epigenetic changes occur during early developmental stages, they may increase the risk of developing PTSD following trauma exposure. Conversely, if these epigenetic changes occur in adulthood, they may influence neuronal apoptosis and survival mechanisms.

Serum cytokines and inflammatory proteins in individuals with heroin use disorder: potential mechanistically based biomarkers for diagnosis

Opioid use disorders cause major morbidity and mortality, and there is a pressing need for novel mechanistic targets and biomarkers for diagnosis and prognosis. Exposure to mu-opioid receptor (MOR) agonists causes changes in cytokine and inflammatory protein networks in peripheral blood, and also in brain glia and neurons. Individuals with heroin use disorder (iHUD) show dysregulated levels of several cytokines in the blood. However, there is limited data on a comprehensive panel of such markers in iHUD versus healthy controls (HC), especially considered as a multi-target biomarker. We used a validated proximity extension assay for the relative quantification of 92 cytokines and inflammatory proteins in the serum of iHUD on medication-assisted therapy (MAT; n = 21), compared to HC (n = 24). Twenty-nine targets showed significant group differences (primarily iHUD>HC), surviving multiple comparison corrections (p = 0.05). These targets included 19 members of canonical cytokine families, including specific chemokines, interleukins, growth factors, and tumor necrosis factor (TNF)-related proteins. For dimensionality reduction, data from these 19 cytokines were entered into a principal component (PC) analysis, with PC1 scores showing significant group differences (iHUD > HC; p < 0.0001). A receiver-operating characteristic (ROC) curve analysis yielded an AUROC = 91.7% (p < 0.0001). This PC1 score remained a positive predictor of being in the HUD group in a multivariable logistic regression, that included select demographic/clinical variables. Overall, this study shows a panel of cytokines that differ significantly between iHUD and HC, providing a multi-target "cytokine biomarker score" for potential diagnostic purposes, and future examination of disease severity.

Serum cytokine and inflammatory markers in individuals with heroin use disorder: potential biomarkers for diagnosis and disease severity

Opioid use disorders cause major morbidity and mortality, and there is a pressing need for novel mechanistic targets and biomarkers for diagnosis and prognosis. Exposure to mu-opioid receptor (MOR) agonists causes changes in cytokine and inflammatory protein networks in peripheral blood, and also in brain glia and neurons. Individuals with heroin use disorder (iHUD) show dysregulated levels of several cytokines in blood. However, there is limited data on a comprehensive panel of such markers in iHUD versus healthy controls (HC), especially as a multi-target biomarker. We used a validated proximity extension assay for relative quantification of 92 cytokines and inflammatory proteins in serum of iHUD on medication assisted therapy (MAT; n=21), versus HC (n=24). Twenty-nine targets showed significant group differences (primarily iHUD>HC), surviving multiple comparison correction (p=0.05). This included 19 members of canonical cytokine families, including specific chemokines, interleukins, growth factors, and tumor necrosis factor (TNF)-related proteins. For dimensionality reduction, data from these 19 cytokines were entered into a principal component (PC) analysis, and PC1 scores were iHUD>HC (p<0.0001). A receiver-operating characteristic (ROC) curve analysis yielded an AUROC=91.7% (p<0.0001). This PC1 score remained a positive predictor of being in the HUD group in a multivariable logistic regression, which included demographic/clinical variables. Overall, this study shows a panel of cytokines that differ significantly between iHUD and HC, and provides a multi-target "cytokine biomarker score" for potential diagnostic purposes, and examination of disease severity.

Biomarkers associated with cognitive impairment in post-traumatic stress disorder: A systematic review of current evidence

OBJECTIVE

This systematic review aimed at synthesizing current evidence on biomarkers associated with cognitive impairment (CI) in Post-Traumatic Stress Disorder (PTSD).

METHODS

A systematic literature search was conducted for studies assessing biomarkers associated with CI in PTSD.

RESULTS

Of the 10,149 titles screened, 8 studies met our inclusion criteria. In a single longitudinal study, MRI volumes, Aβ and tau accumulation were not associated with CI in PTSD. Studies on structural imaging reported no significant association between morphological changes and CI. Two studies on diffusion neuroimaging showed abnormalities in white matter tracts which were cross-sectionally associated with CI in PTSD. Similarly, lower resting-state functional connectivity in neocortical networks, and elevated tau in the neocortex were also cross sectionally associated with CI. Two single studies on biochemical biomarkers showed that sixteen novel plasma proteins and lower BDNF, indicative of genetic vulnerabilities associated with neural and synaptic dysfunctions commonly observed in neurodegeneration, were cross-sectionally associated with CI in PTSD. Overall, evidence is of low quality.

CONCLUSIONS

Longitudinal research utilizing large representative samples of trauma exposed populations are needed to establish the utility of specific biomarkers in monitoring cognitive decline in PTSD.

PTSD and lower respiratory symptoms: A systematic review of longitudinal associations in early 9/11 World Trade Center responders

OBJECTIVE

The objective of this systematic review is to examine longitudinal associations between post-traumatic stress disorder (PTSD) and lower respiratory symptoms (LRS) specifically among responders present at the World Trade Center (WTC) site on September 11, 2001 (9/11). This group, which we refer to as "9/11 early responders," appears to have particularly high rates of both mental and physical illness relative to other 9/11-exposed populations.

METHODS

We performed a systematic literature review to examine associations between PTSD and LRS among 9/11 early responders in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews. After a structured search of Pubmed and the Fire Department of New York (FDNY) WTC bibliography for relevant articles, we identified 4 articles commenting on associations between PTSD and LRS in this population; all 4 passed quality review and were included in our primary analysis. 10 other articles we found in our research discussed rates of PTSD and LRS, but not associations between them, in the population in question; we commented on these in a secondary analysis.

RESULTS

The data demonstrate that there are significant associations between PTSD and LRS among 9/11 early responders. The data also suggest that both of these phenomena are more prevalent among 9/11 early responders relative to other 9/11-exposed populations.

CONCLUSIONS

These findings are relevant for optimizing care for the population in question, as well as for other survivors of past and future disasters with both psychiatric and medical sequelae.

Common genetic variation impacts stress response in the brain

To explain why individuals exposed to identical stressors experience divergent clinical outcomes, we determine how molecular encoding of stress modifies genetic risk for brain disorders. Analysis of post-mortem brain (n=304) revealed 8557 stress-interactive expression quantitative trait loci (eQTLs) that dysregulate expression of 915 eGenes in response to stress, and lie in stress-related transcription factor binding sites. Response to stress is robust across experimental paradigms: up to 50% of stress-interactive eGenes validate in glucocorticoid treated hiPSC-derived neurons (n=39 donors). Stress-interactive eGenes show brain region- and cell type-specificity, and, in post-mortem brain, implicate glial and endothelial mechanisms. Stress dysregulates long-term expression of disorder risk genes in a genotype-dependent manner; stress-interactive transcriptomic imputation uncovered 139 novel genes conferring brain disorder risk only in the context of traumatic stress. Molecular stress-encoding explains individualized responses to traumatic stress; incorporating trauma into genomic studies of brain disorders is likely to improve diagnosis, prognosis, and drug discovery.

Neuroimmune Mechanisms of Opioid Use Disorder and Recovery: Translatability to Human Studies, and Future Research Directions

Opioid use disorder (OUD) is a major current cause of morbidity and mortality. Long-term exposure to short-acting opioids (MOP-r agonists such as heroin or fentanyl) results in complex pathophysiological changes to neuroimmune and neuroinflammatory functions, affected in part by peripheral mechanisms (e.g., cytokines in blood), and by neuroendocrine systems such as the hypothalamic-pituitary-adrenal (HPA) stress axis. There are important findings from preclinical models, but their role in the trajectory and outcomes of OUD in humans is not well understood. The goal of this narrative review is to examine available data on immune and inflammatory functions in persons with OUD, and to identify major areas for future research. Peripheral blood biomarker studies revealed a pro-inflammatory state in persons with OUD in withdrawal or early abstinence, consistent with available postmortem brain studies (which show glial activation) and diffusion tensor imaging studies (indicating white matter disruptions), with gradual abstinence-associated recovery. The mechanistic roles of these neuroimmune and neuroinflammatory changes in the trajectory of OUD (including recovery and medication management) cannot be examined practically with postmortem data. Collection of longitudinal data in larger-scale human cohorts would allow examination of these mechanisms associated with OUD stage and progression. Given the heterogeneity in presentation of OUD, a precision medicine approach integrating multi-omic peripheral biomarkers and comprehensive phenotyping, including neuroimaging, can be beneficial in risk stratification, and individually optimized selection of interventions for individuals who will benefit, and assessments under refractory therapy.

Trauma Matters: Integrating Genetic and Environmental Components of PTSD

Trauma is ubiquitous, but only a subset of those who experience trauma will develop posttraumatic stress disorder (PTSD). In this review, it is argued that to determine who is at risk of developing PTSD, it is critical to examine the genetic etiology of the disorder and individual trauma profiles of those who are susceptible. First, the state of current PTSD genetic research is described, with a particular focus on studies that present evidence for trauma type specificity, or for differential genetic etiology according to gender or race. Next, approaches that leverage non-traditional phenotyping approaches are reviewed to identify PTSD-associated variants and biology, and the relative advantages and limitations inherent in these studies are reflected on. Finally, it is discussed how trauma might influence the heritability of PTSD, through type, risk factors, genetics, and associations with PTSD symptomology.

Treatment-associated mRNA co-expression changes in monocytes of patients with posttraumatic stress disorder

PTSD is a prevalent mental disorder that results from exposure to extreme and stressful life events and comes at high costs for both the individual and society. Therapeutic treatment presents the best way to deal with PTSD-the mechanisms underlying change after treatment, however, remain poorly understood. While stress and immune associated gene expression changes have been associated with PTSD development, studies investigating treatment effects at the molecular level so far tended to focus on DNA methylation. Here we use gene-network analysis on whole-transcriptome RNA-Seq data isolated from CD14⁺ monocytes of female PTSD patients (N = 51) to study pre-treatment signatures of therapy response and therapy-related changes at the level of gene expression. Patients who exhibited significant symptom improvement after therapy showed higher baseline expression in two modules involved in inflammatory processes (including notable examples IL1R2 and FKBP5) and blood coagulation. After therapy, expression of an inflammatory module was increased, and expression of a wound healing module was decreased. This supports findings reporting an association between PTSD and dysregulations of the inflammatory and the hemostatic system and mark both as potentially treatment sensitive.